The warning comes amid international outrage over the Syrian regime’s alleged use of chemical weapons against its own people. “We believe there has been a chemical weapons connection between North Korea and Syria,” Defence Ministry spokesman Kim Min-Seok told reporters.

Any link between North Korea and the attacks in Syria could further isolate Pyongyang, which is prohibited from international sales of its weapons under UN sanctions for conducting nuclear and missile tests.

Suspicions over chemical weapons trade between Pyongyang and Damascus have been raised in the past.

Concerns have grown since South Korea intercepted a North Korean shipment of protective gear on a vessel sailing near the southern port of Busan in 2009, Kim said.